Several new
selective estrogen receptor modulators (
SERMs) are currently under clinical development for the prevention and/or treatment of
postmenopausal osteoporosis, with the goal of optimizing the
estrogen receptor agonist/antagonist activity in target tissues.
Bazedoxifene is a novel
SERM under clinical investigation for the prevention and treatment of
postmenopausal osteoporosis. Emerging clinical data have shown that
bazedoxifene is effective in preventing bone loss and
osteoporotic fractures in postmenopausal women, with no evidence of breast or endometrial stimulation. Two large, prospective, international phase 3 studies have been completed. In postmenopausal women at risk for
osteoporosis,
bazedoxifene has been shown to preserve bone mineral density and to reduce bone turnover. In postmenopausal women with
osteoporosis,
bazedoxifene has demonstrated significant protection against new vertebral fractures and against non-vertebral fractures in women at higher fracture risk. The treatment effects of
bazedoxifene were supported by findings from independent re-analyses using the Fracture Risk Assessment Tool (FRAX), which showed that
bazedoxifene significantly reduced the risk of all clinical and morphometric vertebral fracture and of non-vertebral fracture in women at or above a FRAX-based threshold.
Bazedoxifene was generally safe and well tolerated in the phase 3 studies and showed neutral effects on the breast and an excellent endometrial safety profile; such attributes allow for the partnering of
bazedoxifene with
conjugated estrogens for menopausal symptom relief. Collectively, these results suggest that
bazedoxifene may be a promising new
therapy for the prevention and treatment of
postmenopausal osteoporosis as a monotherapy or in combination with
conjugated estrogens in menopausal
hormone therapy.